Pension and Other Postretirement Benefits - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 109	$ 166	$ 320	$ 520
Interest cost	2,487	1,272	7,452	3,949
Expected return on plan assets	(2,033)	(1,942)	(6,056)	(6,038)
Actuarial loss (gain) amortization	103	238	308	743
Prior service cost (income) amortization	18	3	26	8
Net periodic benefit cost (income)	684	(263)	2,050	(818)
Other Postretirement Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0	1	0	1
Interest cost	14	8	51	19
Expected return on plan assets	0	0	0	0
Actuarial loss (gain) amortization	(36)	(23)	(95)	(70)
Prior service cost (income) amortization	(4)	(8)	(12)	(17)
Net periodic benefit cost (income)	$ (26)	$ (22)	$ (56)	$ (67)